前立腺生検にてPSA4.0ng/ml以下で診断された前立腺癌の臨床的検討

Abstract

経直腸前立腺生検でPSA 4.0ng/ml以下にて診断された前立腺癌について検討した.その結果, PSAが3.1～4.0ng/mlでの陽性率は, 1997年1月から2003年3月までは62例中12例(19.4%), 全例に生検を施行した2003年4月以降は45例中7例(15.6%)であった.生検や全摘における病理結果を検討すると, PSA 4.0ng/ml以下の前立腺癌はPSA 4.1～10.0ng/mlのgray zoneの前立腺癌と同様に大半が臨床的に重要な癌であることが示された

The cases of prostate cancer diagnosed at our hospital after the introduction of transrectal ultrasound-guided prostate biopsy were analyzed to ascertain the cancer detection rate among individuals with a prostate-specific antigen (PSA) below 4.0 ng/ml and to assess the pathological characteristics of the prostatectomy specimens. During the period from January 1997 to December 2003, 1, 167 individuals received prostate biopsies at our hospital. Before March 2003, the PSA cut-off level for biopsy was set at 4.0 ng/ml, but a biopsy was sometimes performed if a rectal examination revealed abnormalities or the patient desired a biopsy with a PSA below 4.0 ng/ml. After April 2003, all individuals with a PSA over 3.1 ng/ml were biopsied. The results of the prostate biopsy and the pathology data on radical prostatectomy specimens were compared between individuals with a PSA below 4.0 ng/ml and those with a PSA of 4.1-10 ng/ml. The prostate cancer detection rate among individuals with a PSA between 3.1 and 4.0 ng/ml was 19.4% (12/62) before March 2003 and 15.6% (7/45) after April 2003. The number of cancer-positive core was significantly lower among individuals with a PSA below 4.0 ng/ml. On prostatectomy specimens the percentage of surgical margin positive cases was significantly higher among individuals with a PSA below 4.0ng/ml (17 cases) than those with a PSA of 4.1-10 ng/ml (67 cases), although there was no significant difference between these two groups in terms of the pathological stage and Gleason score. Our results indicate that the prostate cancer detection rate is also high among Japanese men with a PSA below 4.0 ng/ml. The biopsy results and pathological features for prostate cancer with a PSA below 4.0 ng/ml did not differ markedly from prostate cancer with a PSA in the gray zone (4.1-10.0 ng/ml).